The primary purpose of this study was to determine the effectiveness of a therapist-guided Video-game Biofeedback Modulated Exercise (ViBE) program administered via Dance Dance Revolution to improve dynamic balance, gait and mobility in individuals with Huntington's Disease. Secondary aims were to explore whether the ViBE intervention would improve quality of life, fall risk, and neuropsychological functions. The investigators hypothesized that the video-game program would lead to greater improvements in walking, dynamic balance, quality of life, fall risk, and neuropsychological function than a control handheld video game program. Since motivation is essential to the long-term maintenance of an exercise program the investigators were also interested in finding out how successful people with Huntington's Disease were at playing Dance Dance Revolution, what their perceptions were of playing the game, and whether they thought that it was beneficial